app/views/devise/mailer/unlock_instructions.html.erb
<% require 'devise/version' %>
<p><%= t('.greeting', recipient: @resource.email) %></p>
<p><%= t('.message') %></p>
<p><%= t('.instruction') %></p>
<p><%= link_to t('.action'), unlock_url(@resource, unlock_token: (Devise::VERSION.start_with?('3.') ? @token :@resource.unlock_token)) %></p>